Causes and Risk Factors
Scientists do not know the exact cause of gestational diabetes. However, they have a few clues about how it happens and who is at risk.
Hormones
You’ve probably heard a lot about hormones since becoming pregnant. They are a big part of the changes that occur to help your baby grow. Hormones are chemicals that help the body carry out various functions, like building organs and repairing tissues.
During pregnancy, your body produces lots of hormones in an organ called the placenta. The placenta is also the organ that nourishes the growing baby. These extra hormones are important for the baby’s growth. However, some of these hormones also block insulin’s action in the mother’s body, causing resistance to insulin. All pregnant women—with or without gestational diabetes—have some degree of insulin resistance.
To compensate for all this “resistance,” pregnant women make up to three times more insulin than normal. In some cases, a woman’s body cannot make enough insulin to keep up. Scientists think this occurs in gestational diabetes.
Without enough insulin, your body cannot convert glucose into energy and the excess glucose builds up in the blood. Women with gestational diabetes have elevated blood glucose, much like people with type 2 diabetes.
Genes and Family History
Family history plays a role in gestational diabetes: women with a parent or sibling with diabetes are more likely to have gestational diabetes. Scientists suspect that gestational diabetes is more like type 2 than type 1 diabetes. For this reason, they think that similar genes are involved in both gestational and type 2 diabetes. However, there have been very few studies on the genes specifically involved in gestational diabetes, and there is no genetic test to detect gestational diabetes.
Race and Ethnicity
Women who are Hispanic, American Indian, Asian, or African American are more likely to have gestational diabetes than non-Hispanic white women.
Obesity and Age
Just like type 2 diabetes, obesity and age are risk factors for developing gestational diabetes. Women who are 25 years or older or overweight are more likely to have the disorder. Obesity contributes to insulin resistance and negatively affects the body’s ability to use insulin properly. As discussed above, pregnant women already experience some insulin resistance, so any added resistance through excess weight can put you at higher risk for diabetes.
Prevention and Precautions
The best way to prevent gestational diabetes is to eat nutritious foods, be physically active, and maintain a healthy weight. The goal is to get your body in optimum physical shape before you get pregnant. This may include discussions with your doctor about your weight and wellness before you become pregnant.
Risks for Mom and Baby
Most women with gestational diabetes who manage their glucose levels have healthy babies. However, if you do not actively manage your diabetes during pregnancy, there are significant risks to you and the baby.
Babies born to women with gestational diabetes have a higher risk of jaundice and low blood glucose when they are born. In addition, they are at risk for being born larger than normal. This is called macrosomia. During the last half of pregnancy, the baby grows rapidly. A mother’s high blood glucose during the latter half of pregnancy can lead to a larger-than-normal baby. In some cases, the baby can become too large to be delivered vaginally.
Because women with gestational diabetes tend to have larger babies, they also tend to have more cesarean deliveries. A cesarean section (where a baby is delivered surgically) can be a safer option than vaginal delivery when the baby is larger than normal. The baby may also need to be delivered earlier than the due date. Cesarean deliveries, though relatively safe and frequent, put women at higher risk for infections, increased bleeding, prolonged recovery, and other issues.
Also, the baby may need to be delivered early if he or she grows too large too fast. An early delivery puts the baby at higher risk for respiratory distress because the lungs may not be fully matured.
Women with gestational diabetes are also at higher risk for preeclampsia, a condition in pregnancy in which blood pressure is too high. Swelling of legs and arms commonly goes along with this condition. Preeclampsia can be dangerous for the mother and baby and can mean bed rest for the mother until delivery.
In addition, gestational diabetes puts women at higher risk for urinary tract infections and ketones in their urine. Ketones are byproducts produced by the body when it breaks down fat for energy. They can be harmful to the mom and baby, and the best way to prevent them is to keep blood glucose levels on target. Your doctor may ask you to monitor your ketones (see more about ketone testing in chapter 7).
Management and Treatments
Overall, gestational diabetes is treated much like type 2 diabetes. Most women start with meal planning and regular physical activity to try to lower blood glucose levels. If these strategies do not work, your doctor may prescribe insulin.
Treatment for gestational diabetes is based on the results of your oral glucose tolerance test. In some cases, your doctor may recommend changes in your meal plan or physical activity. In other cases, your doctor may recommend that you start taking insulin right away in addition to changes in your meal plan and physical activity.
Blood glucose goals are narrower for pregnant women than for most people with type 2 diabetes. This is due to the harmful effects that high blood glucose can have on a mother and her growing baby. Work with your health care provider to develop individualized goals for your blood glucose before and after meals.
You will probably need to monitor your blood glucose frequently, perhaps four or more times a day. You can read all about glucose monitoring in chapters 6 and 7.
Just like in type 2 diabetes, women with gestational diabetes have a buildup of glucose in the blood because they do not produce enough insulin.
Food and Exercise
Your meal plan during pregnancy is not designed for weight loss. Instead, the goal is to eat the right food at the right time and in the right amount to manage your blood glucose and promote the healthy development of your baby. Food choices play a key role in managing gestational diabetes because of the importance of controlling blood glucose after meals. It’s important that you meet with a registered dietitian. You may set a daily calorie goal based on the amount of weight you should gain during the pregnancy. The dietitian may also help you adjust your carbohydrate intake to help manage your blood glucose levels. For many women, this is enough to keep blood glucose levels within the target range.
Using moderate exercise to lower blood glucose levels can also help. Most women can swim or walk to keep active. You may also focus on limiting the amount of weight you gain, especially if you were obese before pregnancy. Read more about healthy eating and exercise during pregnancy in chapters 10 and 11, respectively.
Lows in Pregnancy
Luckily, dangerous low blood glucose episodes are relatively rare because insulin resistance is so high late in pregnancy. However, if you seem prone to low blood glucose, remember that the safest time to exercise is after meals, when you are less likely to experience lows.
Insulin
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